Most portable Farfisa organs had a 16 pin connector for bass pedals. The standard bass pedals are a standard octave plus one note, from C to C. With the exception of the Mini Compact, most of the Compact Series, VIP Series, and Pro Series organs can take these pedals. Now the pedals are not super cool synthesizers like the Moog Taurus pedals, but instead just a controller for the circuitry onboard the organ. The 16 pins are for each of the 13 note, and 3 for the juice (positive, negative, and ground I imagine).

They come up from time to time on ebay. They are just controllers (no audio from them, they just control the organ like the organ’s keyboard would). The only thing that they would work with is similar organs of the day, if at all.